Originally posted by hll first of all, thank you for your answer FastPhotography
1) do not worry my sunpak is safe, it is the modern one for digital cameras.
2)i think they did not renew the manual, it is the old one. i can sync them up to 1/180th.
my question:
lighting chart gives me aperture, after i set up the iso.
but how can i determine my shutter speed???
did sunpak prepare the lighting chart for the shutter speed 1/60 th???
thanks
1/60 second was the maximum flash synch for many slrs in the days when film was king. Today, most dslrs will synch at higher speeds. The K10D, in particular synchs at a maximum shutter speed of 1/180. For any camera, the maximum synch speed is that speed at which the focal plane shutter is completely open. Above that speed, the trailing shutter begins closing before the leading shutter has finished opening. This means that there is a slit that moves across the sensor, rather than having the entire frame exposed. To see the effect, put your camera in manual mode and set the shutter speed very high, like 1/500 or 1/1000 and take a flash picture. You will see that only part of the frame is exposed.
If the flash is the primary lighting source, the shutter speed is usually irrelevant, as long as it does not exceed the maximum synch speed for your camera. This is because the flash has a much shorter duration, typically 1/1000 second or less.
Shutter speed becomes relevant if you are trying to combine flash and ambient light. In this case, you can set the shutter speed lower so that the ambient light in the room will expose most of the image, but the flash's brief duration will freeze the action of some element of the picture.
I'm not very familiar with the Sunpak 383. If it is an autoflash, then the flash itself has a sensor that "reads" the light returning from the subject. When the flash determines that enough light has reached its sensor (and the assumption is that the flash/sensor is close to the camera), it quenches the flash output, so that no more light reaches the camera. For this reason, the duration of light from an autoflash can vary from 1/1000 second for relatively distant objects to as short as 1/50,000 second for close objects.
With an autoflash, there is usually a chart that says, in effect, for ISO 100 film, set your aperture at xx; for ISO 200, set it at yy; for ISO 400, set it at zz, and so on. As I said, the camera's shutter speed is largely irrelevant. If you flash has multiple power settings, there will be one such list for each power level.